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Advances in the Valorization of Food Waste for Novel Products

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A special issue of Foods (ISSN 2304-8158). This special issue belongs to the section "Food Security and Sustainability".

Deadline for manuscript submissions: closed (15 January 2024) | Viewed by 20127

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Special Issue Editors

Dr. Manuela M. Moreira

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REQUIMTE/LAQV- Instituto Superior de Engenharia do Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal
Interests: agro-food wastes; bioactive compounds; antioxidants; green extraction techniques; value added products; food; biochar production; agroforestry wastes; contaminants; adsorption

Dr. Francisca Rodrigues

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REQUIMTE/LAQV—Superior Institute of Engineering of Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal
Interests: natural extracts; bioactive compounds; antioxidants; in vitro assays; in vivo cosmetic assays; pharmaceutics
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Cristina Delerue-Matos

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Instituto Superior de Engenharia do Porto, 4249-015 Porto, Portugal
Interests: chromatographic determinations; electrochemistry; sensors/biosensors; sample preparation; environment and food control; environmental monitoring; contaminant detection; PAHs; pesticides; pharmaceuticals; heavy metals; allergens
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In recent years, there has been an increasing amount of interest in recovering bioactive compounds from agricultural, forestry, and food industry wastes, aiming to reduce their environmental impact and simultaneously improve the sustainability of economy and society. The recovery of these compounds involves several steps, where the extraction technique is one of the most important techniques. Furthermore, due to their recognized health properties, such as antioxidant, antimicrobial, and anti-inflammatory activities, the recovered compounds can be incorporated in food, cosmetic, and pharmaceutical products, giving them an extra value.

Despite the large number of publications on the extraction of bioactive compounds from agro-food wastes, there is still a great deal of interest in the topic and a lack of papers regarding the incorporation of the obtained natural extracts.

This Special Issue welcomes research articles and reviews that could fill the gap between research and industrial applications, addressing the new advances in biowaste valorization for novel product application. Manuscripts devoted to the extraction of bioactive compounds from agro-food wastes and their chemical and safety characterization are also welcome. Particular attention will be given to manuscripts that demonstrate the application of the obtained extracts in new products and evaluate their effect.

An integrated approach to the challenge of sustainable food systems: adaptive and mitigatory strategies to address climate change and malnutrition (https://www.nibio.no/en/projects/systemic).

Dr. Manuela M. Moreira
Dr. Francisca Rodrigues
Prof. Dr. Cristina Delerue-Matos
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Foods is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

food waste valorization
bioactive compounds
green extraction techniques
safety assessment
food applications
non-food applications

Published Papers (10 papers)

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Research

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17 pages, 650 KiB

Open AccessArticle

Blueberry Pruning Wastes: From an Undervalued Agricultural Residue to a Safe and Valuable Source of Antioxidant Compounds for the Food Industry

by Olena Dorosh, Virgínia Cruz Fernandes, Cristina Delerue-Matos and Manuela M. Moreira

Foods 2024, 13(2), 317; https://0-doi-org.brum.beds.ac.uk/10.3390/foods13020317 - 19 Jan 2024

Viewed by 793

Abstract

Blueberry fruits have been widely explored for their rich composition of bioactive compounds with recognized health benefits. In contrast, blueberry pruning waste (BPW), generated during the pruning stages of blueberries, has been typically overlooked, even though it can represent a potential source of natural antioxidants. This study aims to characterize the value-added compounds extracted from BPW using green techniques, namely microwave-assisted and subcritical water extraction. The total phenolic content ranged from 157 ± 5 to 335 ± 12 mg GAE/g dw, while the radical scavenging activity determined by a DPPH assay varied from 223 ± 21 to 453 ± 21 mg Trolox equivalents/g dw. Additionally, to ensure the safe application of BPW and its extracts, a screening of pesticides and several environmental contaminants was conducted. Chlorpyrifos-methyl was quantified at a concentration of 4.27 µg/kg in a Bluecrop variety collected in 2019; however, none of the studied compounds were found in the extracts. Despite the presence of a pesticide, this level was below the maximum residue limits for blueberry crops. The results of this study demonstrated the potential of this agro-industrial residue as a natural source of bioactive compounds with high antioxidant activity for food industry applications. Full article

(This article belongs to the Special Issue Advances in the Valorization of Food Waste for Novel Products)

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18 pages, 1238 KiB

Open AccessEditor’s ChoiceArticle

Olive Oil Waste as a Source of Functional Food Ingredients: Assessing Polyphenolic Content and Antioxidant Activity in Olive Leaves

by Carolina L. Ronca, Sara S. Marques, Alberto Ritieni, Rafael Giménez-Martínez, Luisa Barreiros and Marcela A. Segundo

Foods 2024, 13(2), 189; https://0-doi-org.brum.beds.ac.uk/10.3390/foods13020189 - 06 Jan 2024

Cited by 2 | Viewed by 1153

Abstract

Around two million tons of olive oil are produced in Europe annually, with Portugal being among the top five European olive oil-producing countries. Olive oil production results in a substantial amount of waste in the form of olive leaves. These discarded olive leaves contain valuable phenolic compounds with antioxidant, anti-inflammatory, hypoglycaemic, neuroprotective, and antiproliferative properties. Due to their richness in polyphenols with health-promoting properties, olive leaves can be considered a potential functional food ingredient. Thus, sustainable practices for reusing olive leaf waste are in demand. In this study, the polyphenolic content in olive leaves from different Portuguese locations was determined using HPLC-UV-Vis after defining the best fit-for-purpose liquid extraction strategy. The differences in the in vitro antioxidant activity in these samples were determined by several methodologies based on radical scavenging (against 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-2-picrylhydrazyl (DPPH), and peroxyl radical (ORAC)) and on reducing properties (cupric-reducing antioxidant capacity (CUPRAC), and Folin–Ciocalteu assay (FC)), to unveil the relationship between the profile and quantity of polyphenols with antioxidant mechanisms and their capacity. At last, the stability of extracted compounds upon lyophilization and exposition to surrogate biological fluids was assessed, envisioning the future incorporation of olive leaves extracted compounds in food products. Full article

(This article belongs to the Special Issue Advances in the Valorization of Food Waste for Novel Products)

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16 pages, 1534 KiB

Open AccessArticle

A Two-Step Approach to Orange Peel Waste Valorization: Consecutive Extraction of Pectin and Hesperidin

by Onofre Figueira, Verónica Pereira and Paula C. Castilho

Foods 2023, 12(20), 3834; https://0-doi-org.brum.beds.ac.uk/10.3390/foods12203834 - 19 Oct 2023

Cited by 3 | Viewed by 1586

Abstract

Citrus consumption translates into large amounts of residue, the disposal of which is associated with environmental issues and high costs. Current trends in citrus waste focus on the extraction of highly valued bioactive compounds via single-compound extraction. There is a lack of knowledge on how these methodologies can be introduced into extraction schemes of bioactive compounds, maximizing the residue potential and reducing its amount. The present work aimed to address this issue by designing a consecutive extraction of pectin and hesperidin from orange peel waste. A novel method for extraction and precipitation of hesperidin with an eco-friendly approach is also presented. After neutral pretreatment, pectin extraction was conducted under acidic conditions, followed by hesperidin extraction with a drastic pH change. Pectin had a high AUA content (66.20 ± 1.25%), meeting the criteria for use in the food industry. The best-tested conditions for hesperidin extraction (30 min, 70 °C, 1:10 (w/v)) provided a yield of 1% and a purity of 84%. The designed extraction scheme shows the potential of citrus waste as a source of bioactive compounds of good quality and high interest in the food industry while following the principles of green chemistry and circular economy. Full article

(This article belongs to the Special Issue Advances in the Valorization of Food Waste for Novel Products)

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18 pages, 1407 KiB

Open AccessArticle

Camellia japonica Flowers as a Source of Nutritional and Bioactive Compounds

by Antia G. Pereira, Lucia Cassani, Chao Liu, Ningyang Li, Franklin Chamorro, João C. M. Barreira, Jesus Simal-Gandara and Miguel A. Prieto

Foods 2023, 12(15), 2825; https://0-doi-org.brum.beds.ac.uk/10.3390/foods12152825 - 25 Jul 2023

Cited by 1 | Viewed by 1963

Abstract

In recent decades, plants have strengthened their relevance as sources of molecules potentially beneficial for health. This underpinning effect also arises from the extensive research that has been conducted on plants that are typically undervalued, besides being scarcely used. This is the case with Camellia japonica in Galicia (NW Spain), where, despite its abundance, it is exclusively used for ornamental purposes and has been studied only for its proximate composition. Thus, the present study was conducted on several additional parameters in the flowers of eight C. japonica varieties. Our results show that camellia has a high nutritional value, with carbohydrates as the most abundant macronutrients followed by a moderate protein content (4.4–6.3 g/100 g dry weight) and high levels of polyunsaturated fatty acids (especially ω-3 fatty acids, which represent 12.9–22.7% of the total fatty acids), raising its potential for use for nutritional purposes. According to the thermochemical characterization and elemental composition of camellia, the raw material has poor mineralization and low nitrogen content, but high percentages of volatile matter and high carbon-fixation rates, making it a promising alternative for biofuel production. Furthermore, preliminary analysis reveals a high concentration of different bioactive compounds. As a result of these findings, camellias can be used as food or functional ingredients to improve the nutritional quality of food formulations. Full article

(This article belongs to the Special Issue Advances in the Valorization of Food Waste for Novel Products)

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9 pages, 1275 KiB

Open AccessArticle

Techno-Economic Analysis of the Multiple-Pass Ultrasonication with Mechanical Homogenization (MPUMH) Processing of Processed Carrot Discards to Puree

by Gagan Jyot Kaur, Deepak Kumar, Valerie Orsat and Ashutosh Singh

Foods 2023, 12(1), 157; https://0-doi-org.brum.beds.ac.uk/10.3390/foods12010157 - 28 Dec 2022

Viewed by 1609

Abstract

A sustainable valorization process for puree processing from processed carrot discards (PDCs) was proposed by using multiple-pass ultrasonication with mechanical homogenization (MPUMH), optimized at 9 min ultrasonication followed by mechanical homogenization for 1 min, subjected to three passes. Techno-economic analysis of the puree processing plant was studied for two process models using SuperPro Designer for a plant with a capacity of 17.4 MT/day, operational for 26 weeks, with a 20-year lifetime. The two scenarios were (i) base case (PDCs processed without peels and crowns) and (ii) case 2 (PDCs and carrots (50:50, w/w) processed with peels and crowns). Both scenarios were economically feasible with an internal rate of return (IRR) and return on investment (ROI) at 24.71% and 31.04% (base case) and 86.11% and 119.87% (case 2), respectively. Case 2 had a higher total capital investment (Can$13.7 million) but a lower annual operating cost (Can$8.9 million), resulting in greater revenue generation (Can$29.7 million), thus offering a higher ROI. Sensitivity analysis related to the number of passes on puree quality and price is suggested to lower the capital investment. For the base case, a lower ROI was due to the high labor cost incurred for manual peeling of PDCs, indicating the critical need for developing a commercial peeler equipped to cut labor costs and increase profitability. The study casts insights into the techno-economic performance of a sustainable process for the valorization of PDCs. Full article

(This article belongs to the Special Issue Advances in the Valorization of Food Waste for Novel Products)

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14 pages, 2526 KiB

Open AccessArticle

Sustainable Valorization of Litsea cubeba (Lour.) Pers. Residue as the New Lauric Oil Source Using Alternative Green Extraction and Refining Methods

by Ying Li, Xiaoci Zhuang, Xinrui Wu, Chaoying Qiu and Yong Wang

Foods 2022, 11(14), 2047; https://0-doi-org.brum.beds.ac.uk/10.3390/foods11142047 - 11 Jul 2022

Cited by 4 | Viewed by 1809

Abstract

Litsea cubeba is an ethnic woody oil plant, in which essential oil rather than oil has been the main foreign trade product through the decades. Concerning large amounts of residue generated from L. cubeba essential oil processing, a sustainable valorization pathway of these biowastes is proposed in this study. First, such biowastes have been systematically investigated for the first time regarding their oils extracted by three extraction methods, where ultrasound-assisted extraction (UAE) could significantly improve the extraction rate of traditional pressing and solvent extraction without any changes in oil quality. Moreover, the composition of acylglycerols and fatty acids in L. cubeba fruit, kernel, and peel oils were also first identified, which further proved that peels with abundant free fatty acids could lead to high acid value of L. cubeba fruit oils. Compared to virgin coconut oils, L. cubeba kernel oils have a more balanced fatty acid composition with a high lauric acid level, which could be applied as a promising lauric oil resource. Considering the high acid value in L. cubeba kernel oils, both decoloration using activated clay and alkali deacidification were attempted, where the combination of alkali deacidification and 10% of activated clay performed the best considering both quality and cost. Full article

(This article belongs to the Special Issue Advances in the Valorization of Food Waste for Novel Products)

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15 pages, 2317 KiB

Open AccessArticle

Valorization of Spent Coffee Grounds as a Natural Source of Bioactive Compounds for Several Industrial Applications—A Volatilomic Approach

by Carolina Andrade, Rosa Perestrelo and José S. Câmara

Foods 2022, 11(12), 1731; https://0-doi-org.brum.beds.ac.uk/10.3390/foods11121731 - 13 Jun 2022

Cited by 5 | Viewed by 2718

Abstract

Coffee is one of the most popular beverages worldwide, whose production and consumption result in large amounts of waste, namely spent coffee grounds, constituting an important source of compounds for several industrial applications. This work focused on the establishment of the volatile fingerprint of five spent coffee grounds from different geographical origins using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS), as a strategy to identify volatile organic metabolites (VOMs) with potential application in the food industry as antioxidant, anti-inflammatory, and antiproliferative agents. One hundred eleven VOMs belonging to different chemical families were identified, of which 60 were found in all spent coffee grounds analyzed. Furanic compounds (34%), nitrogen compounds (30%), and esters (19%) contributed significant to the total volatile fingerprint. The data obtained suggest that spent coffee grounds have great potential to be used as raw material for different approaches in the food industry towards the development of new food ingredients or products for human consumption, in addition to pharmaceutical and cosmetic applications, namely as antioxidant (e.g., limonene, carvacrol), antimicrobial (e.g., pyrrole-2-carboxaldehyde, β-myrcene) and anti-inflammatory (e.g., furfural, 2-furanmethanol) agents, promoting their integral valorization within the circular bioeconomy concept. Full article

(This article belongs to the Special Issue Advances in the Valorization of Food Waste for Novel Products)

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15 pages, 1063 KiB

Open AccessArticle

Arabinoxylans Release from Brewers’ Spent Grain Using Extrusion and Solid-State Fermentation with Fusarium oxysporum and the Antioxidant Capacity of the Extracts

by Joel G. Cervantes-Ramirez, Francisco Vasquez-Lara, Alberto Sanchez-Estrada, Rosalba Troncoso-Rojas, Erick Heredia-Olea and Alma R. Islas-Rubio

Foods 2022, 11(10), 1415; https://0-doi-org.brum.beds.ac.uk/10.3390/foods11101415 - 13 May 2022

Cited by 6 | Viewed by 2245

Abstract

Brewers’ spent grain (BSG) is the most abundant byproduct generated from the beer-brewing process. BSG is a material rich in hemicellulose, composed of arabinoxylans (AX). However, the high crosslinking of this material causes low availability of AX, for which it is necessary to apply different treatments. The objective of this research is to increase the release of arabinoxylans through solid-state fermentation with Fusarium oxysporum f. sp. lycopersici using extruded brewery spent grain. First, the BSG is subjected to two types of physical treatments: extrusion at 20% moisture, 200 rpm and 50 °C (BSGe), and blade milling (BSGm). The chemical composition is determined for each sample (BSG, BSGe and BSGm). Subsequently, the solid-state fermentation process (SSF) is carried out on each sample. The fermentation kinetics at 30 °C are monitored for 7 days. Once the SSF concludes, AX are extracted, and the purity of AX is determined by the phloroglucinol colorimetric assay. Finally, the total phenolic compounds, phenolic acids and antioxidant capacity by DPPH are quantified. No significant differences (p ≥ 0.05) in the protein, lipid, ash or total dietary fiber contents are found among the samples. No significant difference (p ≥ 0.05) in the content of soluble fiber is found, although BSGe and BSGm have higher values than BSG. On the other hand, the yields of soluble AX exhibit significant differences (p ≤ 0.05) among nonfermented samples (BSG, 0.03%; BSGm, 0.53%; BSGe, 0.70%) and with SSF (BSG, 2.95%; BSGm, 6.24%; and BSGe, 9.58%). In addition, the contents of free phenolic compounds and free phenolic acids and the percent inhibition of free extracts by 2,2-diphenyl-1-picrylhydrazyl (DPPH) differ significantly (p ≤ 0.05) between samples subjected to SSF and nonfermented samples. Therefore, extrusion and SSF treatment increase AX release from BSG as well as the antioxidant capacity of the extracts. Full article

(This article belongs to the Special Issue Advances in the Valorization of Food Waste for Novel Products)

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Review

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34 pages, 5333 KiB

Open AccessReview

From Waste to Resource: Valorization of Lignocellulosic Agri-Food Residues through Engineered Hydrochar and Biochar for Environmental and Clean Energy Applications—A Comprehensive Review

by Silvia Escudero-Curiel, Alba Giráldez, Marta Pazos and Ángeles Sanromán

Foods 2023, 12(19), 3646; https://0-doi-org.brum.beds.ac.uk/10.3390/foods12193646 - 02 Oct 2023

Cited by 1 | Viewed by 1574

Abstract

Agri-food residues or by-products have increased their contribution to the global tally of unsustainably generated waste. These residues, characterized by their inherent physicochemical properties and rich in lignocellulosic composition, are progressively being recognized as valuable products that align with the principles of zero waste and circular economy advocated for by different government entities. Consequently, they are utilized as raw materials in other industrial sectors, such as the notable case of environmental remediation. This review highlights the substantial potential of thermochemical valorized agri-food residues, transformed into biochar and hydrochar, as versatile adsorbents in wastewater treatment and as promising alternatives in various environmental and energy-related applications. These materials, with their enhanced properties achieved through tailored engineering techniques, offer competent solutions with cost-effective and satisfactory results in applications in various environmental contexts such as removing pollutants from wastewater or green energy generation. This sustainable approach not only addresses environmental concerns but also paves the way for a more eco-friendly and resource-efficient future, making it an exciting prospect for diverse applications. Full article

(This article belongs to the Special Issue Advances in the Valorization of Food Waste for Novel Products)

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21 pages, 1167 KiB

Open AccessReview

Hydrothermal Conversion of Food Waste to Carbonaceous Solid Fuel—A Review of Recent Developments

by Moonis Ali Khan, Bassim H. Hameed, Masoom Raza Siddiqui, Zeid A. Alothman and Ibrahim H. Alsohaimi

Foods 2022, 11(24), 4036; https://0-doi-org.brum.beds.ac.uk/10.3390/foods11244036 - 14 Dec 2022

Cited by 6 | Viewed by 2417

Abstract

This review critically discussed recent developments in hydrothermal carbonization (HTC) of food waste and its valorization to solid fuel. Food waste properties and fundamentals of the HTC reactor were also covered. The review further discussed the effect of temperature, contact time, pressure, water–biomass ratio, and heating rate on the HTC of food waste on the physiochemical properties of hydrochar. Literature review of the properties of the hydrochar produced from food waste in different studies shows that it possesses elemental, proximate, and energy properties that are comparable to sub-bituminous coal and may be used directly as fuel or co-combusted with coal. This work conclusively identified the existing research gaps and provided recommendation for future investigations. Full article

(This article belongs to the Special Issue Advances in the Valorization of Food Waste for Novel Products)

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